Strange tire grip fact.

[RandyO]

Countersteering works only becuse the front tire slides into the corner


I'd be willing to bet that diferent surfaces have a different "best %" of slippage at maximum hookup, look at how much flat trackers are spinnin it up, they're the guys that would know about the subject

[Tabby]

Countersteering works only becuse the front tire slides into the corner

No! the front tire is NOT sliding during a countersteer input. It is as Stromper noted. After the desired angle is reached, countersteer pressure at the handlebar is decreased or ceased. Then the bike is in a steady state of cornering, that is dependent on the loading of the tires/chassis that the rider wishes to maintain. Yes, some bikes, because of the way they are designed, may need a certain amount of handlebar pressure to maintain a given cornering arc, that doesn't mean they are in a constant cornersteer mode.
I am talking about pavement riding, and not dirt riding. The videos that we used to show as part of the previous MSF curriculum, used to show that process quite clearly. Once the "CS" input ceased levering the tire out from under the bike, the tire returned to what might be called a camber steer position with the appropriate steering head angle needed to maintain the desired arc.

[RandyO]

No! the front tire is NOT sliding during a countersteer input. It is as Stromper noted. After the desired angle is reached, countersteer pressure at the handlebar is decreased or ceased. Then the bike is in a steady state of cornering, that is dependent on the loading of the tires/chassis that the rider wishes to maintain. Yes, some bikes, because of the way they are designed, may need a certain amount of handlebar pressure to maintain a given cornering arc, that doesn't mean they are in a constant cornersteer mode.
I am talking about pavement riding, and not dirt riding. The videos that we used to show as part of the previous MSF curriculum, used to show that process quite clearly. Once the "CS" input ceased levering the tire out from under the bike, the tire returned to what might be called a camber steer position with the appropriate steering head angle needed to maintain the desired arc.

Did I say anything about countersteering after initiating the turn... NO

only that the front tire slides momentarily while you countersteer, which is the reason you see scalloping wear on the front tire, especially noticable if your air pressure is too low

[Tabby]

Saying that tire scalloping is the result of "sliding", is a bit extreme, I think. I would call scalloping a result of rhythmic squirming of the carcass and rubber, that isn't really felt by the rider, or is largely absorbed by the tire carcass and the suspension, during a turn.
Calling it squirm, or scrub, instead of slide, may be a debate in semantics. I still stand by my statement, the the tire is NOT sliding during the "CS" input. Lower tire pressure would indeed support the idea of carcass squirm.

[butcher bergs]

If there isn't ANY breaking of traction then where does the heat come from?


Oh and BTW; tread design can natually scallop regardless of anything else to do with riding.

[scottieducati]

Bergs, heat is not caused by spinning. Heat in the tires is caused primarily by carcass deflection.

[Tabby]

A good portion of the heat comes from the internal friction of the carcass plies against each other, as they deform to conform to the surface. If you look at a picture of a tire in mid corner, it sure isn't round where it meets the surface. That is why you play with tire pressures to regulate tire temperature.
The lower the temp, more carcass deformation, more friction, higher temps.

[butcher bergs]

I know the answer but I'll play anyway:

All of the heat comes from tire deformation?

Sliding doesn't generate some of the heat?

[butcher bergs]

To clarify, why do you suppose tires wear out? Because they are, in essence, constantly slipping.....in a straight line, cornering, accel, decel.....if those hoops are turning they are slipping in some way.

[Tabby]

Hey, I said a "good portion" of the heat. Not being a tire engineer, I can only give you what this feeble brain can just barely get a handle on. I'm sure that sliding does generate a localized surface heat. Garry McCoy pretty much proved that one. With as much sliding as he was known for, many wondered why his tires didn't shag themselves faster than his peers on a given day. Apparently, a sliding tire may have a high surface temp, but isn't squirming the carcass as much, so internal temps don't climb as fast. You must notice that your tires do get warm, even if you aren't sliding all over the place. Sure, some of that heat comes from the ambient surface temp also, but I'd guess the bulk of it is from internal carcass friction.

As far as tires wearing out from the slipping you are talking about, come on, aren't you getting a bit nit picky here. Of course that is happening too, just not to the degree that you can feel your bike "slipping" all over the place. Geez! That kind of "slip" is part of the, dare I say it, "normal" functioning of a tire.